They’re a new online music retailer and are currently offering up 10 free remixes from top pop artists (Rihanna, Lady Gaga, Madonna, etc) at http://www.masterbeat.com/free.
A bit more info about the site:
+ A new major online music superstore
+ 2 million+ tracks from all major labels as well as individual DJs and smaller labels in a wide variety of genres
+ Lossless files as well as MP3
+ Everything is DRM-free
+ Exclusive remixes unreleased anywhere else
+ A rev share/affiliate program for blogs and artists